Although Testosterone and Related Anabolic Steroids Clearly Increase Muscle Mass

Although testosterone and related anabolic steroids clearly increase muscle mass during puberty,it has been more difficult to determine scientifically whether adult men with normal testosterone can get much stronger from extra steroids,partly because

A) pure steroids have not been available for medical research.
B) no drug company will fund the research.
C) it would be unethical to expose research participants to the high doses of multiple steroids reportedly used by athletes.
D) the FDA doesn't want to find out that they might really work.